Conversely, in malignant settings, the results of ancillary techniques were crucial to provide a second diagnostic level; in particular, specific cluster of differentiation (CD) co-expressions shown by FC, coupled with cytological features and ICC findings, suggested a specific subtype in 26 cases, mostly histologically confirmed (i.e., a small cell population co-expressing CD19/CD10 and CD5- was diagnostic for FL, while CD23/CD5 co-expression was consistent with CLL/SLL; finally, ICC nuclear positivity for cyclin D1 in a CD5+ cell population was diagnostic for MCL). The gene discussed is FCER2; the disease is B-cell chronic lymphocytic leukemia.